// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2009-2010 Gael Guennebaud <gael.guennebaud@inria.fr>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#include "common.h"

struct scalar_norm1_op
{
	typedef RealScalar result_type;
	EIGEN_EMPTY_STRUCT_CTOR(scalar_norm1_op)
	inline RealScalar operator()(const Scalar& a) const { return numext::norm1(a); }
};
namespace Eigen {
namespace internal {
template<>
struct functor_traits<scalar_norm1_op>
{
	enum
	{
		Cost = 3 * NumTraits<Scalar>::AddCost,
		PacketAccess = 0
	};
};
}
}

// computes the sum of magnitudes of all vector elements or, for a complex vector x, the sum
// res = |Rex1| + |Imx1| + |Rex2| + |Imx2| + ... + |Rexn| + |Imxn|, where x is a vector of order n
RealScalar
EIGEN_CAT(REAL_SCALAR_SUFFIX, EIGEN_BLAS_FUNC(asum))(int* n, RealScalar* px, int* incx)
{
	//   std::cerr << "__asum " << *n << " " << *incx << "\n";
	Complex* x = reinterpret_cast<Complex*>(px);

	if (*n <= 0)
		return 0;

	if (*incx == 1)
		return make_vector(x, *n).unaryExpr<scalar_norm1_op>().sum();
	else
		return make_vector(x, *n, std::abs(*incx)).unaryExpr<scalar_norm1_op>().sum();
}

int
EIGEN_CAT(i, EIGEN_BLAS_FUNC(amax))(int* n, RealScalar* px, int* incx)
{
	if (*n <= 0)
		return 0;
	Scalar* x = reinterpret_cast<Scalar*>(px);

	DenseIndex ret;
	if (*incx == 1)
		make_vector(x, *n).unaryExpr<scalar_norm1_op>().maxCoeff(&ret);
	else
		make_vector(x, *n, std::abs(*incx)).unaryExpr<scalar_norm1_op>().maxCoeff(&ret);
	return int(ret) + 1;
}

int
EIGEN_CAT(i, EIGEN_BLAS_FUNC(amin))(int* n, RealScalar* px, int* incx)
{
	if (*n <= 0)
		return 0;
	Scalar* x = reinterpret_cast<Scalar*>(px);

	DenseIndex ret;
	if (*incx == 1)
		make_vector(x, *n).unaryExpr<scalar_norm1_op>().minCoeff(&ret);
	else
		make_vector(x, *n, std::abs(*incx)).unaryExpr<scalar_norm1_op>().minCoeff(&ret);
	return int(ret) + 1;
}

// computes a dot product of a conjugated vector with another vector.
int
EIGEN_BLAS_FUNC(dotcw)(int* n, RealScalar* px, int* incx, RealScalar* py, int* incy, RealScalar* pres)
{
	//   std::cerr << "_dotc " << *n << " " << *incx << " " << *incy << "\n";
	Scalar* res = reinterpret_cast<Scalar*>(pres);

	if (*n <= 0) {
		*res = Scalar(0);
		return 0;
	}

	Scalar* x = reinterpret_cast<Scalar*>(px);
	Scalar* y = reinterpret_cast<Scalar*>(py);

	if (*incx == 1 && *incy == 1)
		*res = (make_vector(x, *n).dot(make_vector(y, *n)));
	else if (*incx > 0 && *incy > 0)
		*res = (make_vector(x, *n, *incx).dot(make_vector(y, *n, *incy)));
	else if (*incx < 0 && *incy > 0)
		*res = (make_vector(x, *n, -*incx).reverse().dot(make_vector(y, *n, *incy)));
	else if (*incx > 0 && *incy < 0)
		*res = (make_vector(x, *n, *incx).dot(make_vector(y, *n, -*incy).reverse()));
	else if (*incx < 0 && *incy < 0)
		*res = (make_vector(x, *n, -*incx).reverse().dot(make_vector(y, *n, -*incy).reverse()));
	return 0;
}

// computes a vector-vector dot product without complex conjugation.
int
EIGEN_BLAS_FUNC(dotuw)(int* n, RealScalar* px, int* incx, RealScalar* py, int* incy, RealScalar* pres)
{
	Scalar* res = reinterpret_cast<Scalar*>(pres);

	if (*n <= 0) {
		*res = Scalar(0);
		return 0;
	}

	Scalar* x = reinterpret_cast<Scalar*>(px);
	Scalar* y = reinterpret_cast<Scalar*>(py);

	if (*incx == 1 && *incy == 1)
		*res = (make_vector(x, *n).cwiseProduct(make_vector(y, *n))).sum();
	else if (*incx > 0 && *incy > 0)
		*res = (make_vector(x, *n, *incx).cwiseProduct(make_vector(y, *n, *incy))).sum();
	else if (*incx < 0 && *incy > 0)
		*res = (make_vector(x, *n, -*incx).reverse().cwiseProduct(make_vector(y, *n, *incy))).sum();
	else if (*incx > 0 && *incy < 0)
		*res = (make_vector(x, *n, *incx).cwiseProduct(make_vector(y, *n, -*incy).reverse())).sum();
	else if (*incx < 0 && *incy < 0)
		*res = (make_vector(x, *n, -*incx).reverse().cwiseProduct(make_vector(y, *n, -*incy).reverse())).sum();
	return 0;
}

RealScalar
EIGEN_CAT(REAL_SCALAR_SUFFIX, EIGEN_BLAS_FUNC(nrm2))(int* n, RealScalar* px, int* incx)
{
	//   std::cerr << "__nrm2 " << *n << " " << *incx << "\n";
	if (*n <= 0)
		return 0;

	Scalar* x = reinterpret_cast<Scalar*>(px);

	if (*incx == 1)
		return make_vector(x, *n).stableNorm();

	return make_vector(x, *n, *incx).stableNorm();
}

int
EIGEN_BLAS_FUNC(
	EIGEN_CAT(REAL_SCALAR_SUFFIX,
			  rot))(int* n, RealScalar* px, int* incx, RealScalar* py, int* incy, RealScalar* pc, RealScalar* ps)
{
	if (*n <= 0)
		return 0;

	Scalar* x = reinterpret_cast<Scalar*>(px);
	Scalar* y = reinterpret_cast<Scalar*>(py);
	RealScalar c = *pc;
	RealScalar s = *ps;

	StridedVectorType vx(make_vector(x, *n, std::abs(*incx)));
	StridedVectorType vy(make_vector(y, *n, std::abs(*incy)));

	Reverse<StridedVectorType> rvx(vx);
	Reverse<StridedVectorType> rvy(vy);

	// TODO implement mixed real-scalar rotations
	if (*incx < 0 && *incy > 0)
		internal::apply_rotation_in_the_plane(rvx, vy, JacobiRotation<Scalar>(c, s));
	else if (*incx > 0 && *incy < 0)
		internal::apply_rotation_in_the_plane(vx, rvy, JacobiRotation<Scalar>(c, s));
	else
		internal::apply_rotation_in_the_plane(vx, vy, JacobiRotation<Scalar>(c, s));

	return 0;
}

int
EIGEN_BLAS_FUNC(EIGEN_CAT(REAL_SCALAR_SUFFIX, scal))(int* n, RealScalar* palpha, RealScalar* px, int* incx)
{
	if (*n <= 0)
		return 0;

	Scalar* x = reinterpret_cast<Scalar*>(px);
	RealScalar alpha = *palpha;

	//   std::cerr << "__scal " << *n << " " << alpha << " " << *incx << "\n";

	if (*incx == 1)
		make_vector(x, *n) *= alpha;
	else
		make_vector(x, *n, std::abs(*incx)) *= alpha;

	return 0;
}
